Polyester resin aqueous dispersion

Abstract

The purpose of the present invention is to provide a polyester resin aqueous dispersion in which dispersibility of a polyester resin is excellent, and the polyester resin aqueous dispersion exhibits good storage stability and high adhesive strength.　The polyester resin aqueous dispersion is characterized by comprising a polyester resin (A), wherein: the content of trivalent or higher polycarboxylic acid components is 0.5-10.0 mol% with respect to all polycarboxylic acid components taken as 100 mol%; the reduced viscosity of the polyester resin (A) is 0.50 dl / g or more; the acid value (AV) of the polyester resin (A) is 100 eq / t or more; and the acid value (AVd) of carboxy groups belonging to a dicarboxylic acid component constituting the main polyester chain is 80 eq / t or more.

Description

Polyester resin aqueous dispersion

[0001] This invention relates to an aqueous dispersion of polyester resin.

[0002] High molecular weight polyester resins, composed of polycarboxylic acid and polyhydric alcohol components, are widely used as binder components in paints, inks, adhesives, and coatings due to their excellent film-forming properties, resistance to organic solvents (solvent resistance), weather resistance, and adhesion to various substrates. In recent years, in particular, there has been a trend to restrict the use of organic solvents from the standpoint of environmental protection, resource conservation, regulations on hazardous materials under the Fire Service Act, and improvement of the workplace environment. As a result, there has been active development of polyester resin aqueous dispersions, in which polyester resin is finely dispersed in an aqueous medium, as polyester resin-based binders that can be used in the above applications.

[0003] To achieve a stable aqueous dispersion of polyester resin, the polyester resin must first have a high acid value. As disclosed in Patent Documents 1 to 3, in order to increase the acid value of the polyester resin, a prepolymer is generally obtained by esterifying a polycarboxylic acid component with a polyhydric alcohol component, and then modification with an acid anhydride is performed.

[0004] Japanese Patent Publication No. 2014-208741, Japanese Patent Publication No. 2013-75966, International Publication No. 2024 / 157683

[0005] Increasing the molecular weight of the polyester resin blended into the aqueous dispersion and thereby increasing its reduced viscosity is effective in improving adhesive strength. However, in the method described in Patent Document 1, when attempting to increase the molecular weight of the polyester resin and thus its reduced viscosity, the number of hydroxyl groups in the polyester resin decreases relatively, reducing the number of reaction sites with acid anhydrides and limiting the number of carboxyl groups that can be introduced. It is also possible to copolymerize polyfunctional monomers to increase the number of reaction sites, but increasing the amount of copolymerization causes the polyester resin to gel before the molecular weight can be increased. Even if the molecular weight can be increased, it decreases significantly during the reaction with acid anhydrides. Patent Document 2 obtains a high molecular weight and high acid value polyester resin by using dianhydrides in the addition reaction. However, because dianhydrides have many reaction sites, attempting to increase the molecular weight leads to problems such as the generation of microgels and large variations in molecular weight. Furthermore, when this resin is dispersed in aqueous dispersion, problems arise such as poor dispersion due to the aforementioned microgels and poor storage stability due to the reaction of dianhydrides at the polymer ends over time. Although Patent Document 3 has obtained a polyester resin with high molecular weight and high acid value, it contains a large amount of easily detachable tricarboxylic acid terminals and unreacted tricarboxylic acid-derived acid value, which hinders micelle formation during water dispersion and leads to poor storage stability.

[0006] This invention was made against the backdrop of the aforementioned prior art problems. Specifically, the object of this invention is to provide a polyester resin aqueous dispersion that exhibits excellent dispersibility, good storage stability, and high adhesive strength.

[0007] As a result of diligent research, the inventors of the present invention have found that the above-mentioned problems can be solved by the means described below, and have arrived at the present invention. That is, the present invention consists of the following configuration.

[0008] [1] The polyester resin (A) contains 0.5 to 10.0 mol% of trivalent or higher polycarboxylic acid components out of 100 mol% of the total polycarboxylic acid components, has a reduced viscosity of 0.50 dl / g or more, has an acid value (AV) of 100 eq / t or more, and has an acid value (AV) of the carboxyl group belonging to the dicarboxylic acid component constituting the main chain of the polyester. ｄ[1] A polyester resin aqueous dispersion characterized by containing a polyester resin (A) having a carboxyl content of 80 eq / t or more. [2] The polyester resin aqueous dispersion according to [1], wherein the amount of unreacted tricarboxylic acid monomer is 500 ppm or less. [3] The polyester resin aqueous dispersion according to [1] or [2], wherein the content of the tricarboxylic acid component in which three carboxyl groups in the polyester resin (A) form an ester bond is 1.0 mol% or more with respect to the total amount of polycarboxylic acid constituting the polyester resin (A). [4] The polyester resin aqueous dispersion according to any one of [1] to [3], wherein the antimony content is 150 ppm or less. [5] The polyester resin aqueous dispersion according to any one of [1] to [4], wherein the dicarboxylic acid component constituting the polyester resin (A) is one or more selected from the group consisting of aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, and aromatic dicarboxylic acid. [6] The polyester resin aqueous dispersion according to any one of [1] to [5], wherein the weight-average molecular weight (Mw) of the polyester resin (A) is 20,000 to 500,000. [7] The polyester resin aqueous dispersion according to any one of [1] to [6], wherein the polycarboxylic acid component with tetravalent or higher is 6 mol% or less in 100 mol% of the polycarboxylic acid constituting the polyester resin (A). [8] The polyester resin aqueous dispersion according to any one of [1] to [7], wherein the solid content concentration of the polyester resin (A) in the polyester resin aqueous dispersion is 10 to 45% by mass. [9] The polyester resin aqueous dispersion according to any one of [1] to [8], wherein the content of the polyester resin (A) in 100% by mass of the resin contained in the polyester resin aqueous dispersion is 20% by mass or more.

[10] The polyester resin aqueous dispersion according to any one of [1] to [9], wherein the content of the organic solvent in 100% by mass of the polyester resin aqueous dispersion is 30% by mass or less.

[11] An adhesive composition comprising an aqueous dispersion of polyester resin according to any one of [1] to

[10] .

[0009] According to the present invention, a polyester resin aqueous dispersion is obtained that exhibits excellent dispersibility of polyester resin, good storage stability, and high adhesive strength.

[0010] <Polyester Resin Aqueous Dispersion> The polyester resin aqueous dispersion of the present invention contains 0.5 to 10.0 mol% of trivalent or higher polycarboxylic acid components in 100 mol% of the total polycarboxylic acid components, the reduced viscosity of the polyester resin (A) is 0.50 dl / g or more, the acid value (AV) of the polyester resin (A) is 100 eq / t or more, and the acid value (AV) of the carboxyl group belonging to the dicarboxylic acid component constituting the main chain of the polyester is ｄ The present invention is characterized by containing a polyester resin (A) having a density of 80 eq / t or more.

[0011] <Polyester Resin (A)> Polyester resin (A) has a chemical structure obtained by polycondensation of a polycarboxylic acid component and a polyhydric alcohol component, preferably having a chemical structure obtained by polycondensation of a dicarboxylic acid component and a trivalent or higher polycarboxylic acid component (including tricarboxylic acid components and tetravalent or higher polycarboxylic acid components) and a diol component. In this disclosure, the polycarboxylic acid component includes a dicarboxylic acid component, a trivalent polycarboxylic acid component (tricarboxylic acid), and a tetravalent or higher polycarboxylic acid component, and the polyhydric alcohol component includes a diol component and a trivalent or higher polyhydric alcohol component. Furthermore, the various polycarboxylic acids exemplified below include not only the polycarboxylic acid itself, but also esters of the polycarboxylic acid and polycarboxylic acid anhydrides.

[0012] The dicarboxylic acid component and the diol component each consist of one or more selected components. The dicarboxylic acid component constituting the polyester resin (A) is not particularly limited, but the dicarboxylic acids or their esters and dicarboxylic acid anhydrides shown below can be used. Specifically, examples of dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids. Examples of aliphatic dicarboxylic acids include adipic acid, sebacic acid, dimer acid, fumaric acid, maleic acid, succinic acid, etc. Examples of alicyclic dicarboxylic acids include 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, methyltetrahydrophthalic acid, etc. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 2,5-frandicarboxylic acid, 5-sodium sulfodimethylisophthalic acid and their esters and acid anhydrides can be used. Among these, aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferred as the dicarboxylic acid component, and it is more preferable that at least aromatic dicarboxylic acids are included. Preferred aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and 2,5-franzicarboxylic acid; more preferably terephthalic acid, isophthalic acid, orthophthalic acid, and 2,5-franzicarboxylic acid; and even more preferably terephthalic acid and isophthalic acid. When aromatic dicarboxylic acids are included, the aromatic dicarboxylic acid component is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, and particularly preferably 70 mol% or more, in 100 mol% of the dicarboxylic acid component constituting the polyester resin (A). It is also preferable to use terephthalic acid and isophthalic acid in combination as aromatic dicarboxylic acids, and their content ratio (terephthalic acid:isophthalic acid) is preferably 5:95 to 95:5, more preferably 20:80 to 80:20, even more preferably 30:70 to 70:30, and particularly preferably 40:60 to 60:40, on a molar basis. By keeping the amounts of terephthalic acid and isophthalic acid within the aforementioned range, it is possible to create an aqueous dispersion that better balances water dispersibility and storage stability.

[0013] From the standpoint of compliance with food hygiene laws in various countries, it is preferable that the polyester resin (A) contains a small amount of aromatic dicarboxylic acid having a sulfonic acid group (e.g., sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5(4-sulfophenoxy)isophthalic acid, etc.). The content of aromatic dicarboxylic acid having a sulfonic acid group in 100 mol% of polycarboxylic acid components is preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, even more preferably 1 mol% or less, and particularly preferably 0 mol%.

[0014] The diol component constituting the polyester resin (A) is not particularly limited, but examples include aliphatic diols, alicyclic diols, aromatic diols, and bisphenol skeleton-containing monomers. Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-methyl-1,3-hexanediol, and 2-methyl-1,3-hexanediol. Tyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-propyl-1,3-propanediol, 2,2-di-n-propyl-1,3-propanediol, 2-n-butyl-2-ethyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, dimergio Examples of diols that can be used include aliphatic diols, diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, polypropylene glycol, etc., as alicyclic diols, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, etc., as aromatic diols, diphenolic acids, etc., as bisphenol skeleton-containing monomers, bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol AP, bisphenol BP, bisphenol P, bisphenol PH, bisphenol S, bisphenol Z, 4,4'-dihydroxybenzophenone, bisphenol fluorene and their hydrogenated products, and glycols such as ethylene oxide adducts and propylene oxide adducts obtained by adding 1 to several moles of ethylene oxide or propylene oxide to the hydroxyl group of bisphenols. Aliphatic diols and alicyclic diols are preferred as diols.When aliphatic diols and alicyclic diols are included, the diol component constituting the polyester resin (A) is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and particularly preferably 90 mol% or more, and may be 100 mol%. Examples of aliphatic diols include C. ２－６ Aliphatic diols are more preferred, and among alicyclic diols, 1,4-cyclohexanedimethanol is more preferred. Furthermore, it is preferable to use ethylene glycol and neopentyl glycol in combination as aliphatic diols, and the content ratio of these (ethylene glycol:neopentyl glycol) on a molar basis is preferably 5:95 to 95:5, more preferably 20:80 to 80:20, even more preferably 30:70 to 70:30, and particularly preferably 40:60 to 60:40. By using the above content ratio, it is possible to create an aqueous dispersion that better balances water dispersibility and storage stability.

[0015] Polyester resin (A) can also be copolymerized with lactones or lactams. For example, ε-caprolactone and ε-caprolactam can be used.

[0016] The polycarboxylic acid and polyhydric alcohol components that make up the polyester resin (A) can be made from raw materials derived from biomass resources. Biomass resources include materials that are stored when sunlight energy is converted into starch, cellulose, etc. through the photosynthesis of plants, the bodies of animals that grow by eating plants, and products made by processing plant or animal bodies. Among these, plant resources are more preferred as biomass resources, and examples include wood, rice straw, rice husks, rice bran, old rice, corn, sugarcane, cassava, sago palm, okara, corn cob, tapioca residue, bagasse, vegetable oil residue, potatoes, buckwheat, soybeans, oils and fats, waste paper, papermaking residue, fishery residue, livestock excrement, sewage sludge, food waste, etc. More preferably are corn, sugarcane, cassava, and sago palm. Specific examples of polycarboxylic acid raw materials derived from biomass resources include, for example, adipic acid, sebacic acid, fumaric acid, itaconic acid, terephthalic acid, and 2,5-franzicarboxylic acid. Specific examples of polyhydric alcohol raw materials derived from biomass resources include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol.

[0017] Polyester resin (A) is copolymerized with a polycarboxylic acid component of trivalent or higher, and it is particularly preferable that a tricarboxylic acid component is copolymerized. These components allow for the introduction of a branched structure into the main chain of polyester resin (A), contributing to the high molecular weight of polyester resin (A). Of the total 100 mol% of polycarboxylic acid components, the polycarboxylic acid component of trivalent or higher is contained in an amount of 0.5 to 10.0 mol%, preferably 1.0 to 8.0 mol%, more preferably 1.2 to 6.0 mol%, and even more preferably 1.5 to 4.0 mol%. If the amount falls below the lower limit, it becomes difficult to obtain polyester resin (A) with a high acid value (AV, AVd) and high molecular weight. If the amount exceeds the upper limit, gelation may occur during manufacturing.

[0018] Examples of tricarboxylic acid components include trivalent aromatic carboxylic acids such as trimellitic acid, trimesic acid, and trimellitic anhydride (TMA); trivalent aliphatic carboxylic acids such as citric acid and citric anhydride; and trivalent alicyclic tricarboxylic acids such as 1,2,4-cyclohexanetricarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid, and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. Among these, trivalent aromatic carboxylic acids are preferred, and trimellitic acid or trimellitic anhydride is more preferred. By copolymerizing the tricarboxylic acid component, it becomes easier to introduce the following into the main chain of polyester resin (A): (1) a tricarboxylic acid component in which three carboxyl groups form ester bonds (with the polyester main chain) (hereinafter sometimes referred to as "triester"), (2) a tricarboxylic acid component in which two carboxyl groups form ester bonds (with the polyester main chain) and one carboxyl group exists as a free carboxyl group (hereinafter sometimes referred to as "diester"), and (3) a tricarboxylic acid component in which one carboxyl group forms ester bonds (with the polyester main chain) and two carboxyl groups exist as free carboxyl groups (hereinafter sometimes referred to as "monoester"). The triester can give the polyester a branched structure, thus contributing to the high molecular weight of polyester resin (A). In the diester and monoester, when dispersed in water, the one or two carboxyl groups remaining in a free state are used to form salts with a base, thus contributing to stable water dispersibility and storage stability.

[0019] Polyester resin (A) contains 0.5 to 10.0 mol%, preferably 1.0 to 8.0 mol%, more preferably 1.2 to 6.0 mol%, and even more preferably 1.5 to 4.0 mol% of tricarboxylic acid components out of 100 mol% of total polycarboxylic acid components. If the amount falls below the lower limit, it becomes difficult to increase the acid value of polyester resin (A). If the amount exceeds the upper limit, the amount of triester increases, leading to excessive thickening during the production of polyester resin (A), making it prone to gelation and difficult to control the molecular weight. Furthermore, it is undesirable because the tricarboxylic acid components tend to remain unreacted.

[0020] Examples of polycarboxylic acid components with four or more valencies include aromatic carboxylic acids such as pyromellitic acid, benzophenonetetracarboxylic acid, pyromellitic anhydride (PMDA), and ethylene glycol bistrimellitate dianhydride, as well as aliphatic carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid. These can be used individually or in combination of two or more. The polycarboxylic acid component with four or more valencies is preferably 0 to 6 mol%, more preferably 0 to 3 mol%, even more preferably 0 to 1 mol%, and particularly preferably 0 to 0.5 mol% of 100 mol% of the polycarboxylic acid component of the polyester resin (A). By keeping the amount below the upper limit, the formation of microgels and gelation of the resin can be prevented. Furthermore, it prevents thickening during the production of the polyester resin (A) and makes it easier to control the molecular weight, enabling stable mass production.

[0021] The content of the triester compound in polyester resin (A) is, for example, 0.2 to 2.0 mol%, preferably 0.5 to 10.0 mol%, more preferably 1.0 to 8.0 mol%, even more preferably 1.2 to 6.0 mol%, even more preferably 1.5 to 5.5 mol%, and particularly preferably 1.8 to 5.0 mol%, relative to the total amount of polycarboxylic acid constituting polyester resin (A). Setting it above the lower limit makes it easier to obtain polyester resin (A) that can form a high crosslink density when used in an adhesive composition. Setting it below the upper limit makes it easier to suppress gelation during the production of polyester resin (A). The content of the triester compound is １ It can be measured by H-NMR and TOCSY spectroscopy, for example, １ When using H-NMR and TOCSY spectral measurements, first １ The integral value of the peak derived from the tricarboxylic acid component is calculated by 1H-NMR measurement. Next, by TOCSY spectral measurement, the integral values ​​of the peaks that form triesters and the other peaks of the tricarboxylic acid component are calculated separately, thereby revealing the content of the triester-forming component among the tricarboxylic acid components.

[0022] The proportion of triesters in the trivalent or higher polycarboxylic acid components of polyester resin (A) is preferably 60% or more, more preferably 70% or more, even more preferably 80% or more, and even more preferably 90% or more. There is no particular upper limit, but it may be 100% or less, or 96% or less (i.e., preferably 60-100%, 70-100%, 80-96%, or 90-96%). Within the above range, a branched structure can be sufficiently formed in polyester resin (A), the acid value (AVd) is high, and furthermore, the amount of unreacted trivalent or higher polycarboxylic acid components is reduced because the trivalent or higher polycarboxylic acid components have reacted sufficiently, resulting in polyester resin (A) with excellent water dispersibility and storage stability. For similar reasons, the ratio of mono- or diester compounds in the polyester resin (A) is preferably 40% or less, more preferably 30% or less, even more preferably 20% or less, and even more preferably 10% or less. The lower limit is not particularly limited but may be 0% or more, or 4% or more (i.e., preferably 0-40%, 0-30%, 4-20%, or 4-10%). The ratio of triester compounds and the ratio of mono- or diester compounds can be determined by the method described in the examples.

[0023] Furthermore, the polyester resin (A) may be copolymerized with a polyhydric alcohol component of trivalent or higher valency. Examples of polyhydric alcohol components of trivalent or higher valency include glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol, which can be used individually or in combination of two or more.

[0024] In polyester resin (A), the molecular chain ends of the polyester may be carboxyl groups derived from the dicarboxylic acid component that constitutes the polyester main chain. Polyester resin (A) is also characterized by a large amount of carboxyl groups derived from the dicarboxylic acid component, and the acid value (AV) of the carboxyl groups belonging to the dicarboxylic acid component that constitutes the polyester main chain is also important. ｄ)(is) 80 eq / t or more, preferably 80 to 500 eq / t, preferably 100 to 500 eq / t, more preferably 110 to 450 eq / t, still more preferably 120 to 400 eq / t, and even more preferably 140 to 350 eq / t. By setting it within the above range, the amount of tricarboxylic acid used can be suppressed, leading to suppression of gelation during production. Also, by setting it within the above range, the storage stability of the polyester resin (A) will also be good. Acid value (AV ｄ ) To adjust it within the above range, for example, it is desirable to perform the reaction described later.

[0025] The acid value (AV) of the polyester resin (A) is 100 eq / t or more, preferably 100 to 1000 eq / t, preferably 120 to 1000 eq / t, more preferably 150 to 800 eq / t, and still more preferably 180 to 500 eq / t. By setting it within the above range, the dispersibility of the polyester resin (A) in the aqueous dispersion will be good.

[0026] In the polyester resin (A), a part of the tricarboxylic acid component may remain unreacted, but it is preferable that the amount of the unreacted tricarboxylic acid component is small. Specifically, the monomer amount of the unreacted tricarboxylic acid component in the aqueous dispersion may be, for example, 500 ppm or less, preferably 300 ppm or less, more preferably 200 ppm or less, still more preferably 150 ppm or less, even more preferably 100 ppm or less, and particularly preferably 50 ppm or less. Also, practically, it may be 1 ppm or more, 10 ppm or more, or 20 ppm or more (that is, preferably 1 to 500 ppm, 1 to 300 ppm, 10 to 200 ppm, 10 to 150 ppm, 20 to 100 ppm, or 20 to 50 ppm). By setting the amount of the unreacted tricarboxylic acid component within the above range, the formation of micelles during aqueous dispersion is not inhibited, and a stable aqueous dispersion of particles can be prepared. Furthermore, by setting it within the above range, the storage stability of the aqueous dispersion will also be good. Also, in the polyester resin (A), the acid value (AV ｕ ) derived from the unreacted tricarboxylic acid component is, for example, 0 to 200 eq / t, preferably 1 to 200 eq / t, more preferably 3 to 100 eq / t, and still more preferably 5 to 50 eq / t.

[0027] The hydroxyl value (OHV) of the polyester resin (A) is preferably 70 to 400 eq / t, more preferably 100 to 300 eq / t, and even more preferably 150 to 250 eq / t.

[0028] The reduced viscosity (ηsp / c) of the polyester resin (A) is 0.50 dl / g or higher, preferably 0.50 to 1.4 dl / g, more preferably 0.52 to 1.4 dl / g, more preferably 0.55 to 1.2 dl / g, and even more preferably 0.60 to 1.0 dl / g. Setting it above the lower limit ensures good adhesion when used as an adhesive layer for laminated films. Setting it below the upper limit prevents damage to the substrate film during peeling.

[0029] The number-average molecular weight (Mn) of the polyester resin (A) is preferably 1,000 to 50,000, more preferably 5,000 to 40,000, and even more preferably 9,000 to 30,000.

[0030] The weight-average molecular weight (Mw) of the polyester resin (A) is preferably 20,000 to 500,000, more preferably 60,000 to 400,000, even more preferably 80,000 to 300,000, even more preferably 90,000 to 200,000, and particularly preferably 105,000 to 150,000.

[0031] The dispersion degree (Mw / Mn) of the polyester resin (A) is preferably 5.0 to 50.0, more preferably 10.0 to 45.0, even more preferably 15.0 to 40.0, and even more preferably 20.0 to 35.0.

[0032] The glass transition temperature (Tg) of the polyester resin (A) is preferably -100 to 150°C, more preferably -80 to 120°C, even more preferably -50 to 100°C, and particularly preferably 0 to 90°C.

[0033] The polyester resin (A) can be produced by any known method that can produce a polycondensate of a polycarboxylic acid component and a polyhydric alcohol component, but it is desirable that the method includes, for example, 1) a step of esterifying the polycarboxylic acid component and the polyhydric alcohol component, and 2) a step of polycondensing the reaction product obtained in step 1). Each step will be described in detail below.

[0034] The polycarboxylic acid component and polyhydric alcohol component may be those mentioned above as appropriate, and it is preferable that the polycarboxylic acid component includes a dicarboxylic acid component and a trivalent or higher polycarboxylic acid component. The amount of trivalent or higher polycarboxylic acid component used in step 1) is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more, based on 100 mol% of the total amount of trivalent or higher polycarboxylic acid components added before producing the polyester resin (A). By charging an amount within the above range in step 1), the reaction of these components can be promoted and the amount of unreacted components (preferably unreacted tricarboxylic acid components) can be reduced. Furthermore, even if the amount of trivalent or higher polycarboxylic acid component itself is small, the polyester resin (A) can be made high molecular weight, which also leads to the suppression of gelation.

[0035] The ratio G / A (polyhydric alcohol component / polyhydric carboxylic acid component) of the polyhydric carboxylic acid component to be charged in step 1) is preferably 0.95 to 1.08, more preferably 0.97 to 1.07, even more preferably 0.99 to 1.06, and even more preferably 1.00 to 1.05. By adjusting within the above range, not only oligomers having only hydroxyl groups at the terminals, but also oligomers having both hydroxyl groups and carboxyl groups (preferably carboxyl groups derived from the dicarboxylic acid component) at the terminals can be produced. In the subsequent polycondensation reaction of step 2), the hydroxyl groups react with the polyhydric carboxylic acid of trivalent or higher, for example, forming a triester while introducing a branched structure into the polyester resin (A). This contributes to increasing the molecular weight of the polyester resin (A). On the other hand, many of the terminal carboxyl groups remain at the ends of the polyester resin (A) even after step 2), contributing to increasing the acid value of the polyester resin (A). Furthermore, with this manufacturing method, even if the amount of trivalent or higher polycarboxylic acid component itself is small, the polyester resin (A) can be made to have a high molecular weight, which helps to suppress gelation and reduces the amount of unreacted components.

[0036] In step 1), a polymerization catalyst can be used. As the polymerization catalyst, titanium compounds, antimony compounds, germanium compounds, metal acetates and the like, which are conventionally known polymerization catalysts, can be used. For example, as titanium compounds, tetra-n-butyl titanate, tetraisopropyl titanate, titanium oxyacetylacetonate, etc. can be used; as antimony compounds, antimony trioxide, tributoxyantimony, etc. can be used; as germanium compounds, germanium oxide, tetra-n-butoxygermanium, etc. can be used; as metal acetates, acetates of magnesium, iron, zinc, manganese, cobalt, aluminum, etc. can be used. These can be used alone or in combination of two or more kinds. However, when the amount of the antimony compound used as the polymerization catalyst increases, foreign substances are likely to occur, so it is desirable to use as little antimony as possible. The content of antimony in the aqueous dispersion is preferably 0 to 150 ppm, more preferably 0 to 100 ppm, still more preferably 0 to 50 ppm, even more preferably 0 to 1 ppm, and particularly preferably 0 ppm. It is also possible to contain a small amount of zinc as the polymerization catalyst, but when the amount of zinc used increases, foreign substances are likely to occur, so it is desirable to use as little zinc as possible. The content of zinc in the aqueous dispersion is preferably less than 0 to 40 ppm, more preferably 0 to 30 ppm, still more preferably 0 to 10 ppm, even more preferably 0 to 1 ppm, and particularly preferably 0 ppm. The amount of metal derived from the polymerization catalyst in the aqueous dispersion is determined by the method described in the examples.

[0037] As the polymerization catalyst, it is preferable to use at least a titanium compound. When the total amount of the metal derived from the polymerization catalyst in the aqueous dispersion is 100% by mass, the content of titanium is preferably 10% by mass or more, more preferably 30% by mass or more, still more preferably 50% by mass or more, and particularly preferably 80% by mass or more, and it may be 90% by mass or more. Also, the content of titanium in the aqueous dispersion is preferably 2 ppm or more, more preferably 5 ppm or more, still more preferably 10 ppm or more, and particularly preferably 15 ppm or more.

[0038] The esterification reaction in step 1) is preferably carried out under heating. The reaction temperature is preferably 180 to 280 °C, more preferably 200 to 260 °C. The reaction time is preferably 1 to 10 hours, more preferably 2 to 8 hours.

[0039] In step 2), the reactant (oligomer) obtained in step 1) is polycondensed to produce the polyester resin (A). The polycondensation reaction in step 2) is preferably carried out under heating. The reaction temperature is preferably 180 to 280 °C, more preferably 200 to 260 °C. The reaction time is preferably 0.1 to 5 hours, more preferably 0.5 to 3 hours.

[0040] Step 2) is preferably carried out under vacuum or in an inert atmosphere (such as in a nitrogen stream). Step 2) may be divided into, for example, an initial polymerization and a later polymerization. In the initial polymerization, it is preferably polymerized at 100 mmHg or less (preferably 50 mmHg or less), at 180 to 280 °C (preferably 200 to 260 °C), for 0.1 to 2 hours (preferably 0.2 to 1 hour), and in the later polymerization, it is preferably polymerized at 10 mmHg or less (preferably 5 mmHg or less), at 180 to 280 °C (preferably 200 to 260 °C), for 0.1 to 3 hours (preferably 0.5 to 2 hours).

[0041] After step 2), an acid addition step or a depolymerization step using a tricarboxylic acid component may be further carried out. However, since there is a risk that the hydroxyl groups of the polyester resin (A) may decrease and the tricarboxylic acid component may remain unreacted, it is desirable not to carry out the acid addition step or the depolymerization step using the tricarboxylic acid component after step 2). Even without carrying out the acid addition step or the depolymerization step, the polyester resin (A) has a high acid value.

[0042] <Polyester Resin Aqueous Dispersion> The polyester resin aqueous dispersion of the present invention is an aqueous dispersion containing the polyester resin (A) described above. The polyester resin aqueous dispersion of the present invention may also contain resins other than the polyester resin (A) described above, to the extent that it is suitable for the spirit of the present invention. The content of polyester resin (A) is preferably 20% by mass or more, more preferably 40% by mass or more, even more preferably 60% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, out of 100% by mass of the resin contained in the polyester resin aqueous dispersion.

[0043] The polyester resin aqueous dispersion of the present invention can be prepared by methods such as (i) dissolving polyester resin (A) in an organic solvent in which polyester resin (A) dissolves, and then sequentially adding a basic compound and water as needed to disperse the dispersion; or (ii) adding polyester resin (A), water, an organic solvent in which polyester resin (A) dissolves, and a basic compound as needed, and then heating and dispersing the dispersion. Furthermore, if it is desired to reduce the amount of organic solvent or to completely remove it to obtain an aqueous dispersion, it is also possible to dissolve and disperse using an organic solvent having a boiling point of 100°C or lower, and then remove the solvent by heating or under reduced pressure. In the case of polyester resin, the former method (i) is preferable from the viewpoint of film-forming properties.

[0044] In this case, the temperature at which the polyester resin (A) is dissolved is preferably 40 to 160°C, more preferably 50 to 140°C, even more preferably 60 to 130°C, and most preferably 70 to 100°C. At temperatures above 40°C, the polyester resin (A) dissolves sufficiently, preventing entanglement of molecular chains, while at temperatures below 160°C, thermal degradation of the polyester resin (A) can be suppressed.

[0045] Organic solvents that can dissolve polyester resin (A) by heating in a temperature range of 40 to 160°C include methyl ethyl ketone, cyclohexanone, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, 1,3-dioxolane, 1,2-hexanediol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and triethylene glycol monobutyl ether. In addition to the above, n-butanol, isopropyl alcohol, diacetone alcohol, 2-ethylhexanol, acetonitrile, and 1,3-oxolane may also be used in combination. Among these, methyl ethyl ketone, tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, and isopropyl alcohol, which have boiling points of 100°C or less, are particularly preferred. By using these methods, the amount of organic solvent remaining in the system can be reduced in a short time during the subsequent solvent removal process.

[0046] When the polyester resin (A) is dissolved at a temperature of 100°C or higher, it is preferable to cool the temperature of the polyester resin (A) solution to 100°C or lower, and then, while stirring the resin solution, sequentially add water and, if necessary, a basic compound to perform a phase change and obtain an aqueous dispersion.

[0047] In the present invention, it is preferable to prepare the aqueous dispersion of polyester resin with an organic solvent content of 30% by mass or less in 100% by mass. A content of 30% by mass or less prevents the development of a flash point due to the organic solvent.

[0048] The basic compound used when forming the polyester resin (A) of the present invention into an aqueous dispersion is preferably a compound that volatilizes during the drying and baking processes during film formation, such as ammonia and / or organic amine compounds with a boiling point of 250°C or lower. Preferably, examples include triethylamine, N,N-diethylethanolamine, N,N-dimethylethanolamine, aminoethanolamine, N-methyl-N,N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine, etc. These basic compounds are required in an amount that can at least partially neutralize the carboxyl groups of the polyester resin (A), and specifically, it is desirable to add 0.5 to 1.5 equivalents relative to the carboxyl group equivalents.

[0049] The average particle size of the polyester resin aqueous dispersion according to the present invention is extremely important as it greatly affects the appearance and storage stability of the coating film, and is preferably between 30 and 200 nm. When the average particle size is 200 nm or less, the dispersion is stable and the film-forming properties are also good, resulting in a good appearance of the resulting coating film. Furthermore, by setting the average particle size to 30 nm or more, it is possible to prevent the dispersion particles from fusing or agglomerating.

[0050] The solid content concentration of the polyester resin (A) in the aqueous dispersion of polyester resin of the present invention is preferably 10 to 45% by mass, more preferably 15 to 40% by mass, and even more preferably 20 to 35% by mass. If it is below the upper limit, the viscosity of the aqueous dispersion is appropriate, and aggregation between resin particles is prevented, resulting in good dispersion stability. If it is above the lower limit, it becomes easier to commercialize from both a manufacturing and application perspective.

[0051] The solid content concentration of the polyester resin aqueous dispersion of the present invention is preferably 15 to 60%. Below the lower limit is undesirable because it not only wastes transportation and storage costs but also consumes extra energy and time in the drying process when the aqueous dispersion is put into use. On the other hand, above the upper limit is undesirable because the viscosity of the aqueous dispersion may become very high. It is also undesirable from the viewpoint of storage stability.

[0052] This disclosure further includes adhesive compositions comprising the polyester resin aqueous dispersion of the present invention. The aforementioned polyester resin (A) has high reducing viscosity and excellent adhesive properties, and also has a high acid value, resulting in excellent dispersibility in aqueous dispersions. Therefore, the polyester resin aqueous dispersion of the present invention is suitable as an aqueous dispersion for adhesive applications.

[0053] This application claims the benefit of priority based on Japanese Patent Application No. 2024-171175, filed on 30 September 2024. The entire specification of Japanese Patent Application No. 2024-171175, filed on 30 September 2024, is incorporated herein by reference.

[0054] The present invention will be described in more detail below with reference to examples, but the present invention is not limited by the following examples, and it is certainly possible to implement it with appropriate modifications within the scope that is consistent with the spirit of the preceding and following descriptions, and all such modifications are included within the technical scope of the present invention. In the following, unless otherwise specified, "parts" means "parts by mass" and "%" means "percent mass".

[0055] <Evaluation of Polyester Resin> (1) The resin composition sample was alkaline-decomposed with sodium hydroxide in a mixed solvent of deuterium methanol / dimethyl sulfoxide-d6, and the decomposition solution was diluted with heavy water. Nuclear magnetic resonance (NMR) spectrometer (Bruker "AVANCE NEO 600") and data processing were performed using Bruker TopSpin® 4.0 software. １¹H-NMR measurements were performed. The measurements were conducted under the following conditions: resonance frequency of 600 MHz, waiting time of 1 sec, number of integrations of 64, measurement temperature of 303 K, and a reference heavy water concentration of 4.74 ppm. The resin composition was calculated in moles from the integral ratio. The integral value of the terephthalic acid peak detected at 7.89 ppm was set to 100. Note that even if a monomer other than terephthalic acid (e.g., isophthalic acid or orthophthalic acid) has a clearly defined proton peak position in NMR, it can be used as a reference for the resin composition, and in that case, the integral value of the proton peak of that monomer can be set to 100. The same applies to the "content of TMA triester compounds" described later.

[0056] (2) Reduced viscosity (ηsp / c) 0.1 g of the sample was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 6 / 4), and measured at 30°C using an Ubbelohde viscometer.

[0057] (3) The GPC sample was dissolved or diluted in tetrahydrofuran to a sample concentration of approximately 0.5%, and filtered through a polytetrafluoroethylene membrane filter with a pore size of 0.5 μm to be used as the measurement sample. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the sample were measured by gel permeation chromatography using tetrahydrofuran as the mobile phase and a differential refractometer as the detector, and the degree of dispersion (Mw / Mn) was calculated. The flow rate was 1 mL / min and the column temperature was 30°C. Showa Denko "KF-802", "KF-804L", and "KF-806L" columns were used. Monodisperse polystyrene was used as the molecular weight standard.

[0058] (4) Hydroxyl Value (OHV) The sample was dissolved in chloroform-d alone and in a mixed solvent of chloroform-d and trifluoroacetic acid, and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 and Bruker TopSpin® 4.0 software for data processing, using each solvent. １ ¹H-NMR measurements were performed, the integral values ​​were determined, and the hydroxyl value was calculated by averaging these values.

[0059] (5) Glass transition temperature (Tg) was measured using a differential scanning calorimeter (SII "DSC-200"). 5 mg of the sample was placed in an aluminum container with a retaining lid and sealed. It was cooled to -50°C using liquid nitrogen, and then heated to 150°C at a rate of 20°C / min. In the endothermic curve obtained during this process, the temperature at the intersection of the baseline before the endothermic peak and the tangent line toward the endothermic peak was defined as the glass transition temperature.

[0060] (6) Amount of unreacted TMA: 160 mg of the aqueous dispersion was dried under vacuum at 105°C for 3 hours to obtain a polyester resin. The resin was dissolved in chloroform, and then low-moisture methanol was added and allowed to stand for 36 hours to methylate the anhydrous ring. The supernatant was filtered through a PTFE filter, and the dried residue was dissolved in DMAc. The sample was analyzed using a Shimadzu HPLC to identify the amount of unreacted TMA in the aqueous dispersion. Column: Inertsil ODS-2 5 μm 4.0 mm × 250 mm Mobile phase: A 0.4% phosphoric acid, B acetonitrile Flow rate: 1.0 mL / min Injection volume: 10 μL Detection wavelength: 258 nm

[0061] (7) Samples containing the triester compound of TMA were dissolved in a mixed solvent of chloroform-d / 1,1,1,3,3,3-Hexafluoro-2-propanol-d2 / triethylamine (90 / 10 / 1), and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 spectrometer and Bruker TopSpin® 4.0 software for data processing. １ 1H-NMR and TOCSY spectroscopy measurements were performed. １ The 1H-NMR measurements were performed under the following conditions: resonance frequency of 600.13 MHz, waiting time of 1 sec, number of integrations of 64, measurement temperature of 303 K, and reference level of chloroform at 7.33 ppm. １When the integral value of TPA detected at 8.12 ppm in 1H-NMR was set to 100, the integral value of the peak detected at 7.75–7.85 ppm was defined as Hc. Measurement by the TOCSY method was performed under the following conditions: resonance frequency 600.13 MHz, waiting time 2 sec, pulse width 2.5 msec, mixing time 0.05 sec, number of integrations 16 times, measurement temperature 303 K, and reference chloroform 7.3 ppm. The integral values ​​of the peaks observed at (F1 axis, F2 axis) = (7.8, 8.2) and (7.8, 8.1) in the TOCSY spectrum were defined as Ha and Hb, respectively, and X was calculated using the following formula, with (1) composition mol ratio of terephthalic acid obtained from the resin composition: Hd. Hc is the integral value including components derived from the triester of TMA. By measuring using the TOCSY method, the Hc component is separated into Ha and Hb, and Ha is the integral value containing only the triester. X = Hd / 100 × 4 × Hc × (Ha / (Ha + Hb)) Let X be the content (mol%) of the triester of TMA.

[0062] (8) Acid value (AV) 0.2 g of the sample was dissolved in 20 ml of chloroform and titrated with a methanol solution of 0.1 N sodium methoxide in the presence of phenolphthalein indicator. The point at which the solution turned red was defined as the neutralization point, and the value was converted to the equivalent amount per ton of sample (eq / t).

[0063] (9) Acid value (AV) derived from dicarboxylic acid components ｄ The sample was dissolved in a mixed solvent of chloroform-d / 1,1,1,3,3,3-Hexafluoro-2-propanol-d2 / triethylamine, and nuclear magnetic resonance (NMR) was performed using a Bruker AVANCE NEO 600 spectrometer and Bruker TopSpin® 4.0 software for data processing. １ 1H-NMR measurements were performed, and the content derived from the dicarboxylic acid component was determined from the integrated value, which was then converted into an acid value per ton of sample.

[0064] (10) Amount of Metal Components The amount of metal components contained in the aqueous dispersion was determined based on the following procedure. The polyester resin obtained by drying the aqueous dispersion in a platinum crucible at 105°C under vacuum for 3 hours was weighed, carbonized on an electric stove, and then ashed in a muffle furnace at 550°C for 8 hours. The ashed sample was dissolved in 1.2 M hydrochloric acid to prepare the sample solution. The prepared sample solution was measured under the following conditions, and the concentrations of antimony, titanium, and zinc in the polyester resin were determined by high-frequency inductively coupled plasma atomic emission spectrometry. Apparatus: SPECTRO CIROS-120 Plasma output: 1400W Plasma gas: 13.0 L / min Auxiliary gas: 2.0 L / min Nebulizer: Cross-flow nebulizer Chamber: Cyclone chamber Measurement wavelength: 167.078 nm

[0065] <Evaluation of Polyester Resin Aqueous Dispersions> (11) The particle size of the dispersible aqueous dispersion was evaluated using a concentrated particle size analyzer (Otsuka Electronics Co., Ltd. "FPAR-1000"). Particle size was analyzed using histogram analysis. ○: Average particle size is 200 nm or less ×: Average particle size is greater than 200 nm, or the dispersion is unsuccessful and precipitates

[0066] (12) After the storage-stable aqueous dispersion was left to stand in a constant temperature incubator at 25°C for 6 months, the particle size of the aqueous dispersion was evaluated in the same manner as in the previous section. ○: (Average particle size after stability test) - (Average particle size before stability test) ≤ 100 nm ×: (Average particle size after stability test) - (Average particle size before stability test) > 100 nm, or precipitation occurs in the aqueous dispersion after stability test.

[0067] (13) Adhesion Aqueous dispersion was applied to a 25 μm thick A-PET film to a thickness of 3-4 μm. It was then dried at 140°C for 30 seconds to obtain a laminated film. The coated surface of the evaluation laminated film was heat-sealed to a 25 μm thick A-PET film at a temperature of 150°C and a pressure of 0.2 MPa for 1 second. A 15 mm wide test piece was then cut out, and a 180° peel test was performed at 25°C using a Shimadzu Autograph AG-Xplus at a tensile speed of 200 mm / min to measure the peel strength. ・For aqueous dispersions containing polyester resin with Tg ≥ 50°C ○: Peel strength is 6 N / 15 mm or more ×: Peel strength is less than 6 N / 15 mm ・For aqueous dispersions containing polyester resin with Tg < 50°C ○: Peel strength is 2 N / 15 mm or more ×: Peel strength is less than 2 N / 15 mm

[0068] <Example 1> In a 3 L four-necked flask, 364 parts terephthalic acid, 387 parts isophthalic acid, 27 parts trimellitic anhydride (TMA), 151 parts ethylene glycol, 243 parts neopentyl glycol, and 0.2 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. Subsequently, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 120 minutes to carry out later polymerization. After that, the vacuum was broken to obtain a polyester resin. The composition and various properties of the finally obtained polyester resin are shown in Tables 1 to 3.

[0069] 105 parts of the obtained polyester resin, 105 parts of methyl ethyl ketone, and 35 parts of isopropanol were placed in a 1 L flask. The mixture was heated to 75°C and stirred for 3 hours until completely dissolved. After confirming dissolution, 2.8 parts of N,N-dimethylethanolamine were added and stirred for 30 minutes. Then, 245 parts of pure water were slowly added dropwise, and the mixture was heated to 90°C and stirred until the distillate was gone. The mixture was then filtered through a 200 μm nylon mesh to obtain an aqueous dispersion of polyester resin.

[0070] <Example 2> In a 3 L four-necked flask, 425 parts terephthalic acid, 322 parts orthophthalic acid, 19 parts trimellitic anhydride (TMA), 386 parts 1,2-propanediol, and 0.2 parts tetra-n-butyl titanate were charged. Otherwise, a polyester resin and an aqueous dispersion of polyester resin were obtained in the same manner as in Example 1.

[0071] <Example 3> In a 3 L four-necked flask, 357 parts terephthalic acid, 186 parts isophthalic acid, 227 parts sebacic acid, 17 parts trimellitic anhydride (TMA), 145 parts ethylene glycol, 233 parts neopentyl glycol, and 0.2 parts tetra-n-butyl titanate were charged. Otherwise, the process was the same as in Example 1 to obtain a polyester resin and an aqueous dispersion of polyester resin.

[0072] <Example 4> In a 3 L four-necked flask, 530 parts isophthalic acid, 204 parts adipic acid, 13 parts trimellitic anhydride (TMA), 150 parts ethylene glycol, 275 parts 1,6-hexanediol, and 0.2 parts tetra-n-butyl titanate were charged. Otherwise, a polyester resin and an aqueous dispersion of polyester resin were obtained in the same manner as in Example 1.

[0073] <Example 5> In a 3 L four-necked flask, 196 parts terephthalic acid, 507 parts isophthalic acid, 25 parts TMA, 85 parts ethylene glycol, 177 parts 1,4-butanediol, 178 parts cyclohexanedimethanol, and 0.1 parts tetra-n-butyl titanate were charged. Otherwise, the process was the same as in Example 1 to obtain a polyester resin and an aqueous dispersion of the polyester resin.

[0074] <Example 6> In a 3 L four-necked flask, 328 parts terephthalic acid, 327 parts franzicarboxylic acid, 24 parts TMA, 32 parts ethylene glycol, 263 parts neopentyl glycol, 179 parts cyclohexanedimethanol, and 0.1 parts tetra-n-butyl titanate were charged. Otherwise, a polyester resin and an aqueous dispersion of polyester resin were obtained in the same manner as in Example 1.

[0075] <Example 7> In a 3 L four-necked flask, 199 parts terephthalic acid, 215 parts isophthalic acid, 373 parts dimer acid, 19 parts TMA, 86 parts ethylene glycol, 134 parts neopentyl glycol, 91 parts cyclohexanedimethanol, and 0.1 parts tetra-n-butyl titanate were charged. Otherwise, a polyester resin and an aqueous dispersion of polyester resin were obtained in the same manner as in Example 1.

[0076] <Example 8> In a 3 L four-necked flask, 388 parts terephthalic acid, 359 parts isophthalic acid, 25 parts TMA, 93 parts ethylene glycol, 128 parts 1,2-propanediol, 131 parts cyclohexanedimethanol, 69 parts dimergol, and 0.1 parts tetra-n-butyl titanate were charged. Otherwise, a polyester resin and an aqueous dispersion of polyester resin were obtained in the same manner as in Example 1.

[0077] <Comparative Example 1> In a 3 L four-necked flask, 362 parts terephthalic acid, 378 parts isophthalic acid, 18 parts trimellitic anhydride, 275 parts ethylene glycol, 249 parts neopentyl glycol, and 0.1 parts antimony trioxide were charged. The temperature was then gradually raised to 250°C over 4 hours to carry out the esterification reaction. After that, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 120 minutes to carry out later polymerization to polymerize the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 27 parts TMA was added under a nitrogen atmosphere at 230°C and stirred for 30 minutes. After that, it was removed into a water bath to obtain a polyester resin.

[0078] <Comparative Example 2> In a 3 L four-necked flask, 382 parts terephthalic acid, 382 parts isophthalic acid, 278 parts ethylene glycol, 251 parts neopentyl glycol, and 0.1 parts tetra-n-butyl titanate were charged. The temperature was then gradually increased to 250°C over 4 hours to carry out the esterification reaction. After that, while maintaining the temperature at 250°C, the pressure was reduced to 10 mmHg over 30 minutes to carry out initial polymerization, and then the pressure was reduced to below 1 mmHg for 120 minutes to carry out later polymerization to polymerize the prepolymer. After that, the vacuum was broken and the prepolymer was removed and its physical properties were evaluated. Next, 21 parts pyromellitic anhydride was added under a nitrogen atmosphere at 200°C and stirred for 30 minutes. After that, it was removed into a water bath to obtain a polyester resin.

[0079]

[0080]

[0081]

[0082] In Tables 1-3, abbreviations are used with the following meanings: "TPA": Terephthalic acid "IPA": Isophthalic acid "OPA": Orthophthalic acid "AA": Adipic acid "SA": Sebacic acid "FDCA": Frangicarboxylic acid "DA": Dimer acid "TMA": Trimellitus anhydride "PMDA": Pyromellitic anhydride "EG": Ethylene glycol "NPG": Neopentyl glycol "PG": 1,2-Propanediol "BD": 1,4-Butanediol "HD": 1,6-Hexanediol "CHDM": Cyclohexanedimethanol "DD": Dimerdiol "Ti": Titanium "Sb": Antimony

Claims

1. The polyester resin (A) contains 0.5 to 10.0 mol% of trivalent or higher polycarboxylic acid components out of 100 mol% of the total polycarboxylic acid components, has a reduced viscosity of 0.50 dl / g or higher, has an acid value (AV) of 100 eq / t or higher, and the acid value (AV) of the carboxyl group belonging to the dicarboxylic acid component constituting the main chain of the polyester is... ｄ A polyester resin aqueous dispersion characterized by containing a polyester resin (A) having a concentration of 80 eq / t or more.

2. The aqueous polyester resin dispersion according to claim 1, wherein the amount of unreacted tricarboxylic acid monomer is 500 ppm or less.

3. The polyester resin aqueous dispersion according to claim 1, wherein the content of the tricarboxylic acid component in which three carboxyl groups in the polyester resin (A) form an ester bond is 1.0 mol% or more with respect to the total amount of polycarboxylic acid constituting the polyester resin (A).

4. The polyester resin aqueous dispersion according to claim 1, wherein the antimony content is 150 ppm or less.

5. The polyester resin aqueous dispersion according to claim 1, wherein the polyester resin (A) comprises one or more dicarboxylic acid components selected from the group consisting of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids.

6. The polyester resin aqueous dispersion according to claim 1, wherein the weight-average molecular weight (Mw) of the polyester resin (A) is 20,000 to 500,000.

7. The polyester resin aqueous dispersion according to claim 1, wherein the polycarboxylic acid component constituting the polyester resin (A) is 6 mol% or less of the polycarboxylic acid component with a tetravalent or higher valency in 100 mol%.

8. The polyester resin aqueous dispersion according to claim 1, wherein the solid content concentration of the polyester resin (A) in the polyester resin aqueous dispersion is 10 to 45% by mass.

9. The polyester resin aqueous dispersion according to claim 1, wherein the content of the polyester resin (A) in 100% by mass of the resin contained in the polyester resin aqueous dispersion is 20% by mass or more.

10. The polyester resin aqueous dispersion according to claim 1, wherein the content of an organic solvent is 30% by mass or less of 100% by mass of the polyester resin aqueous dispersion.

11. An adhesive composition comprising a polyester resin aqueous dispersion according to any one of claims 1 to 10.

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